Then Sunday, Aug. 9, on Meet the Press, David Gregory, who has a mane of corn silk above his head, apparently forgot the small matter of the $100 million Mr. Bloomberg is likely to spend to beat a candidate who few New Yorkers think can win anyway, and asked him, “So, Mayor, you can make news here. Will you shave your head for reelection?”

“Let me equivocate on that and, and duck the issue,” Mr. Bloomberg responded. “But I think—my hair is falling out at sufficient rate that I won’t have to shave it. It’s going to be gone.”

The next morning, Mr. Bloomberg appeared at the Patrick Henry Preparatory School on East 103 Street with Schools Chancellor Joel Klein and other city officials.

Mr. Klein, whose pate is tan and oval-shaped and free of even a strand of hair on top, was speaking about the success of the mayor’s education policy when he looked at education activist Laurence Harvey, who wears his abundant hair in an astronaut-helmet-size afro.

“I’m also happy to have Larry Harvey here,” said Mr. Klein, who then paused and looked at the head of Mr. Harvey, 45.

“That’s quite a head of hair, Larry,” said Mr. Klein.

“You wish you had it,” said Mr. Bloomberg, who stood to Mr. Klein’s left.

“The way I see it, life balances out,” said Mr. Klein, philosophically. He then addressed Mr. Harvey. “Between the two of us, we have two heads of hair.”

“Cory Booker yesterday asked me to shave my head,” Mr. Bloomberg said to Mr. Klein. “And you would not have much of a problem with that.”